Input devices that prevent leakage of authentication codes have been known (see Japanese Patent Application Laid-Open No. 2011-44029, for example). Such an input device includes: a touch sensor that accepts an input; a tactile presentation unit that causes the surface of the touch sensor to vibrate; and a control unit that performs control so that the tactile presentation unit presents a tactile feel intermittently to the object in contact with the touch-sensitive surface when the touch sensor accepts an input, and an authentication code based on the number of tactile presentation times is accepted when an input determining operation is detected.
In the above input device, time is used as a trigger to present a tactile feel. Therefore, others can easily guess an input value from the period of time during which the object is in touch with the touch panel.